<!DOCTYPE html>
<html>
<head>
  <title>Fullscreen Video Detection Test</title>
  <meta name=viewport content="width=device-width initial-scale=1.0">
  <style>
    .big {
      /* More than the threshold for "effectively fullscreen" detection. */
      width: 99vw;
      height: 99vh;
    }
    .small {
      /* Less than the threshold for "effectively fullscreen" detection. */
      width: 70vw;
      height: 70vh;
    }
    .portrait {
      width: 18vw;
      height: 99vh;
    }
    .hide {
       display: none;
    }
  </style>
</head>
<body>
    <div id="big_div" class="big">
        <video controls id="big_video" class="big" src="bear.webm"></video>
    </div>
    <div id="small_div" class="small">
      <video controls id="small_video" class="small" src="bear.webm"></video>
    </div>
</body>
<script>
    function makeFullscreen(id) {
      if (!document.fullscreenElement) {
        document.getElementById(id).requestFullscreen();
      }
    }
    function exitFullscreen() {
      document.exitFullscreen();
    }
    function makeBig(id) {
      document.getElementById(id).className = "big";
    }
    function makeSmall(id) {
      document.getElementById(id).className = "small";
    }
    function makePortrait(id) {
      document.getElementById(id).className = "portrait";
    }
    function hide(id) {
      document.getElementById(id).className = "hide";
    }
    function detach(id) {
      let e = document.getElementById(id);
      e.parentNode.removeChild(e);
      window._detached_element = e;
    }
    function attach_to(id) {
      let parent = document.getElementById(id);
      parent.appendChild(window._detached_element);
    }
  </script>
</html>
